Ethyl 8-(4-nitro­phen­yl)imidazo[1,2-a]pyridine-7-carboxyl­ate

Duan, G.-Y.; Zhang, Y.-J.; Hao, B.-Q.

doi:10.1107/S1600536810047938

organic compounds

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ISSN: 2056-9890

Volume 66| Part 12| December 2010| Page o3272

https://doi.org/10.1107/S1600536810047938

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Ethyl 8-(4-nitrophenyl)imidazo[1,2-a]pyridine-7-carboxylate

Gui-Yun Duan,^a ^* Yu-Juan Zhang ^a and Ben-Qian Hao ^a

^aCollege of Pharmaceutical Sciences, Taishan Medical University, Tai an 271016, People's Republic of China
^*Correspondence e-mail: duanguiyun@yahoo.cn

(Received 12 November 2010; accepted 17 November 2010; online 24 November 2010)

In the title compound, C₁₆H₁₃N₃O₄, the imidazo[1,2-a]pyridine and benzene rings make a dihedral angle of 56.21 (2)°. The crystal packing is stabilized by weak π–π stacking interactions [centroid–centroid distances = 3.787 (2) Å] and C—H⋯O intermolecular hydrogen-bonding interactions.

Related literature

For applications of imidazo[1,2-a]pyridine-containing compounds, see: Jia et al. (2010 ).

Experimental

Crystal data

C₁₆H₁₃N₃O₄
M_r = 311.29
Monoclinic, P 2₁ /c
a = 8.189 (4) Å
b = 15.821 (8) Å
c = 11.884 (6) Å
β = 105.380 (8)°
V = 1484.7 (13) Å³
Z = 4
Mo Kα radiation
μ = 0.10 mm⁻¹
T = 273 K
0.26 × 0.19 × 0.13 mm

Data collection

Bruker SMART CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ) T_min = 0.974, T_max = 0.987
7569 measured reflections
2618 independent reflections
1965 reflections with I > 2σ(I)
R_int = 0.023

Refinement

R[F² > 2σ(F²)] = 0.042
wR(F²) = 0.122
S = 1.38
2618 reflections
209 parameters
H-atom parameters constrained
Δρ_max = 0.18 e Å⁻³
Δρ_min = −0.16 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C9—H9B⋯O3ⁱ	0.97	2.59	3.295 (3)	130
Symmetry code: (i) -x, -y, -z.

Data collection: SMART (Bruker, 1998 ); cell refinement: SAINT (Bruker, 1999 ); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL.

Supporting information

Crystal structure: contains datablocks global, I. DOI: https://doi.org/10.1107/S1600536810047938/hg2751sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536810047938/hg2751Isup2.hkl

checkCIF report

Comment top

The imidazo[1,2-a]pyridines (IP) have attracted considerable attention because of their wide range of pharmacological activities such as antiviral, antibacterial, antifungal, antiulcer, and anti-inflammatory behavior (Jia et al., 2010). Drugs containing imidazo[1,2-a]pyridines such as Alpidem, Zolpidem, Necopidem, Olprinone, Divalpon and Zolimidine are currently available on the market. In continuation of our work in this direction, we report here the crystal structure of the title compound, (I).

The title compound, C₁₆H₁₃N₃O₄, the imidazo[1,2-a]pyridine ring (N2/N3/C1—C7) and benzene ring (C11—C16) make a dihedral angles of 56.21 (2) °. π—π interactions are indicated by the short distance (Cg1···Cg2 distance of 3.787 (2) Å, symmetry code: x,1/2 - y,-1/2 + z) between the centroids of the pyridine ring (N2/C3—C7) (Cg1) and benzene ring C11—C16 (Cg2) (Table 1). There are weaker C—H···O intermolecular interactions, which stabilize the structure (Table 1).

Related literature top

For applications of imidazo[1,2-a]pyridine-containing compounds, see: Jia et al. (2010).

Experimental top

To a 50-ml round-bottomed flask were added ethyl 4-bromobut-2-enoate (1.20 mmol), (1H-imidazol-2-yl)(4-nitrophenyl)methanone (1.00 mmol), potassium carbonate (0.283 g, 2.05 mmol) and dry DMF (10 ml). The mixture was stirred at rt for 3 h and then filtered. The filtrate was poured into water (100 ml) and extracted with CH₂Cl₂ (three times per 30 ml). The combined extracts were washed with water, dried over anhydrous MgSO₄ and filtered, and the solvent was removed by rotary evaporation. The crude product were purified by column chromatography. Crystals of (I) suitable for X-ray diffraction was obtained by slow evaporation of a solution of the product in ethyl acetate at room temperature for 2 d.

Structure description top

For applications of imidazo[1,2-a]pyridine-containing compounds, see: Jia et al. (2010).

Computing details top

Data collection: SMART (Bruker, 1998); cell refinement: SAINT (Bruker, 1999); data reduction: SAINT (Bruker, 1999); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top

Fig. 1. View of the title compound (I), with displacement ellipsoids drawn at the 40% probability level.

Ethyl 8-(4-nitrophenyl)imidazo[1,2-a]pyridine-7-carboxylate top

Crystal data top

C₁₆H₁₃N₃O₄	F(000) = 648
M_r = 311.29	D_x = 1.393 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 2224 reflections
a = 8.189 (4) Å	θ = 2.2–28.2°
b = 15.821 (8) Å	µ = 0.10 mm⁻¹
c = 11.884 (6) Å	T = 273 K
β = 105.380 (8)°	Block, colorless
V = 1484.7 (13) Å³	0.26 × 0.19 × 0.13 mm
Z = 4

Data collection top

Bruker SMART CCD area-detector diffractometer	2618 independent reflections
Radiation source: fine-focus sealed tube	1965 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.023
phi and ω scans	θ_max = 25.0°, θ_min = 2.2°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −9→9
T_min = 0.974, T_max = 0.987	k = −18→14
7569 measured reflections	l = −13→14

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.042	H-atom parameters constrained
wR(F²) = 0.122	w = 1/[σ²(F_o²) + (0.0514P)²] where P = (F_o² + 2F_c²)/3
S = 1.38	(Δ/σ)_max = 0.014
2618 reflections	Δρ_max = 0.18 e Å⁻³
209 parameters	Δρ_min = −0.16 e Å⁻³
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.018 (2)

Crystal data top

C₁₆H₁₃N₃O₄	V = 1484.7 (13) Å³
M_r = 311.29	Z = 4
Monoclinic, P2₁/c	Mo Kα radiation
a = 8.189 (4) Å	µ = 0.10 mm⁻¹
b = 15.821 (8) Å	T = 273 K
c = 11.884 (6) Å	0.26 × 0.19 × 0.13 mm
β = 105.380 (8)°

Data collection top

Bruker SMART CCD area-detector diffractometer	2618 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	1965 reflections with I > 2σ(I)
T_min = 0.974, T_max = 0.987	R_int = 0.023
7569 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.042	0 restraints
wR(F²) = 0.122	H-atom parameters constrained
S = 1.38	Δρ_max = 0.18 e Å⁻³
2618 reflections	Δρ_min = −0.16 e Å⁻³
209 parameters

Special details top

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
O1	0.4896 (3)	0.09876 (13)	0.56705 (14)	0.1106 (7)
O2	0.2458 (2)	0.15378 (13)	0.49165 (14)	0.1073 (7)
O3	0.26198 (16)	0.02576 (9)	0.02277 (12)	0.0718 (4)
O4	0.16766 (15)	0.07201 (9)	−0.15928 (11)	0.0664 (4)
N1	0.3843 (3)	0.12901 (12)	0.48549 (16)	0.0745 (5)
N2	0.72970 (16)	0.19702 (9)	−0.06373 (12)	0.0490 (4)
N3	0.80707 (17)	0.22853 (10)	0.12673 (13)	0.0561 (4)
C1	0.8789 (2)	0.24074 (12)	−0.04309 (17)	0.0604 (5)
H1	0.9381	0.2550	−0.0972	0.073*
C2	0.9223 (2)	0.25889 (13)	0.07191 (18)	0.0617 (5)
H2	1.0193	0.2886	0.1096	0.074*
C3	0.6901 (2)	0.19066 (11)	0.04239 (14)	0.0460 (4)
C4	0.53881 (19)	0.14865 (10)	0.04674 (14)	0.0432 (4)
C5	0.4368 (2)	0.11716 (11)	−0.05585 (14)	0.0456 (4)
C6	0.4823 (2)	0.12748 (12)	−0.16214 (14)	0.0521 (5)
H6	0.4108	0.1070	−0.2311	0.063*
C7	0.6262 (2)	0.16622 (12)	−0.16469 (15)	0.0550 (5)
H7	0.6555	0.1721	−0.2347	0.066*
C8	0.2819 (2)	0.06715 (11)	−0.05705 (15)	0.0500 (4)
C9	0.0130 (2)	0.02350 (15)	−0.17049 (19)	0.0762 (6)
H9A	0.0405	−0.0349	−0.1484	0.091*
H9B	−0.0509	0.0467	−0.1197	0.091*
C10	−0.0864 (3)	0.02810 (19)	−0.2914 (2)	0.1084 (9)
H10A	−0.1100	0.0862	−0.3130	0.163*
H10B	−0.1909	−0.0019	−0.3003	0.163*
H10C	−0.0238	0.0031	−0.3407	0.163*
C11	0.4992 (2)	0.14378 (10)	0.16178 (13)	0.0444 (4)
C12	0.6133 (2)	0.10865 (12)	0.25694 (14)	0.0534 (5)
H12	0.7159	0.0879	0.2490	0.064*
C13	0.5773 (2)	0.10392 (12)	0.36384 (15)	0.0576 (5)
H13	0.6541	0.0801	0.4280	0.069*
C14	0.4254 (3)	0.13518 (12)	0.37291 (15)	0.0551 (5)
C15	0.3104 (2)	0.17153 (12)	0.28087 (17)	0.0606 (5)
H15	0.2089	0.1931	0.2897	0.073*
C16	0.3482 (2)	0.17554 (12)	0.17493 (15)	0.0551 (5)
H16	0.2711	0.1999	0.1114	0.066*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.1407 (15)	0.1542 (18)	0.0415 (9)	−0.0163 (13)	0.0320 (10)	0.0017 (10)
O2	0.1239 (15)	0.1407 (17)	0.0844 (12)	−0.0061 (12)	0.0754 (11)	−0.0159 (10)
O3	0.0773 (9)	0.0782 (10)	0.0643 (9)	−0.0097 (7)	0.0263 (7)	0.0181 (7)
O4	0.0542 (8)	0.0928 (11)	0.0517 (8)	−0.0126 (7)	0.0132 (6)	0.0050 (7)
N1	0.1072 (15)	0.0807 (13)	0.0470 (11)	−0.0257 (11)	0.0407 (11)	−0.0149 (9)
N2	0.0456 (8)	0.0610 (9)	0.0463 (9)	0.0069 (7)	0.0227 (7)	0.0053 (7)
N3	0.0464 (9)	0.0705 (11)	0.0539 (9)	0.0020 (7)	0.0180 (8)	−0.0055 (8)
C1	0.0479 (11)	0.0750 (13)	0.0668 (13)	0.0025 (9)	0.0298 (10)	0.0064 (10)
C2	0.0440 (10)	0.0723 (13)	0.0731 (14)	0.0006 (9)	0.0230 (10)	−0.0030 (10)
C3	0.0459 (10)	0.0546 (10)	0.0422 (10)	0.0116 (8)	0.0199 (8)	0.0030 (8)
C4	0.0446 (9)	0.0490 (10)	0.0405 (9)	0.0096 (7)	0.0193 (8)	0.0046 (7)
C5	0.0484 (9)	0.0523 (10)	0.0397 (10)	0.0070 (8)	0.0179 (8)	0.0038 (8)
C6	0.0534 (10)	0.0671 (12)	0.0383 (10)	0.0034 (9)	0.0166 (8)	0.0020 (8)
C7	0.0609 (11)	0.0726 (13)	0.0382 (10)	0.0078 (9)	0.0247 (9)	0.0057 (9)
C8	0.0550 (11)	0.0536 (11)	0.0463 (11)	0.0053 (8)	0.0221 (9)	−0.0001 (8)
C9	0.0588 (12)	0.0869 (16)	0.0848 (17)	−0.0171 (11)	0.0225 (11)	0.0004 (12)
C10	0.0882 (18)	0.117 (2)	0.102 (2)	−0.0324 (16)	−0.0065 (15)	0.0071 (16)
C11	0.0499 (10)	0.0496 (10)	0.0381 (9)	0.0030 (8)	0.0192 (8)	0.0013 (7)
C12	0.0544 (10)	0.0637 (12)	0.0454 (10)	0.0073 (9)	0.0186 (9)	0.0024 (8)
C13	0.0681 (12)	0.0668 (12)	0.0369 (10)	−0.0044 (10)	0.0120 (9)	0.0033 (8)
C14	0.0756 (13)	0.0571 (11)	0.0410 (10)	−0.0129 (10)	0.0302 (9)	−0.0087 (8)
C15	0.0675 (12)	0.0658 (12)	0.0605 (12)	0.0065 (10)	0.0380 (10)	−0.0009 (10)
C16	0.0573 (11)	0.0651 (12)	0.0500 (11)	0.0121 (9)	0.0269 (9)	0.0087 (9)

Geometric parameters (Å, º) top

O1—N1	1.212 (2)	C6—C7	1.336 (2)
O2—N1	1.221 (2)	C6—H6	0.9300
O3—C8	1.199 (2)	C7—H7	0.9300
O4—C8	1.324 (2)	C9—C10	1.453 (3)
O4—C9	1.456 (2)	C9—H9A	0.9700
N1—C14	1.467 (2)	C9—H9B	0.9700
N2—C7	1.362 (2)	C10—H10A	0.9600
N2—C1	1.368 (2)	C10—H10B	0.9600
N2—C3	1.387 (2)	C10—H10C	0.9600
N3—C3	1.331 (2)	C11—C12	1.379 (2)
N3—C2	1.368 (2)	C11—C16	1.382 (2)
C1—C2	1.349 (3)	C12—C13	1.380 (2)
C1—H1	0.9300	C12—H12	0.9300
C2—H2	0.9300	C13—C14	1.369 (3)
C3—C4	1.419 (2)	C13—H13	0.9300
C4—C5	1.376 (2)	C14—C15	1.367 (3)
C4—C11	1.488 (2)	C15—C16	1.375 (2)
C5—C6	1.418 (2)	C15—H15	0.9300
C5—C8	1.492 (2)	C16—H16	0.9300

C8—O4—C9	116.01 (15)	O4—C8—C5	111.70 (14)
O1—N1—O2	123.67 (18)	C10—C9—O4	108.03 (18)
O1—N1—C14	118.0 (2)	C10—C9—H9A	110.1
O2—N1—C14	118.4 (2)	O4—C9—H9A	110.1
C7—N2—C1	131.00 (15)	C10—C9—H9B	110.1
C7—N2—C3	122.27 (14)	O4—C9—H9B	110.1
C1—N2—C3	106.67 (15)	H9A—C9—H9B	108.4
C3—N3—C2	104.42 (15)	C9—C10—H10A	109.5
C2—C1—N2	105.78 (16)	C9—C10—H10B	109.5
C2—C1—H1	127.1	H10A—C10—H10B	109.5
N2—C1—H1	127.1	C9—C10—H10C	109.5
C1—C2—N3	112.23 (17)	H10A—C10—H10C	109.5
C1—C2—H2	123.9	H10B—C10—H10C	109.5
N3—C2—H2	123.9	C12—C11—C16	119.08 (15)
N3—C3—N2	110.90 (14)	C12—C11—C4	120.61 (15)
N3—C3—C4	130.12 (15)	C16—C11—C4	120.30 (14)
N2—C3—C4	118.97 (15)	C11—C12—C13	120.87 (16)
C5—C4—C3	117.92 (14)	C11—C12—H12	119.6
C5—C4—C11	124.50 (15)	C13—C12—H12	119.6
C3—C4—C11	117.56 (15)	C14—C13—C12	118.25 (17)
C4—C5—C6	120.44 (16)	C14—C13—H13	120.9
C4—C5—C8	121.03 (14)	C12—C13—H13	120.9
C6—C5—C8	118.43 (15)	C15—C14—C13	122.45 (16)
C7—C6—C5	120.98 (17)	C15—C14—N1	118.81 (18)
C7—C6—H6	119.5	C13—C14—N1	118.74 (19)
C5—C6—H6	119.5	C14—C15—C16	118.54 (17)
C6—C7—N2	119.39 (15)	C14—C15—H15	120.7
C6—C7—H7	120.3	C16—C15—H15	120.7
N2—C7—H7	120.3	C15—C16—C11	120.80 (17)
O3—C8—O4	123.14 (17)	C15—C16—H16	119.6
O3—C8—C5	125.15 (17)	C11—C16—H16	119.6

C7—N2—C1—C2	177.07 (17)	C9—O4—C8—C5	178.48 (15)
C3—N2—C1—C2	−0.19 (19)	C4—C5—C8—O3	−27.4 (3)
N2—C1—C2—N3	0.1 (2)	C6—C5—C8—O3	149.05 (18)
C3—N3—C2—C1	0.1 (2)	C4—C5—C8—O4	154.15 (15)
C2—N3—C3—N2	−0.17 (18)	C6—C5—C8—O4	−29.4 (2)
C2—N3—C3—C4	−179.10 (17)	C8—O4—C9—C10	−173.05 (19)
C7—N2—C3—N3	−177.32 (15)	C5—C4—C11—C12	125.59 (19)
C1—N2—C3—N3	0.23 (18)	C3—C4—C11—C12	−56.1 (2)
C7—N2—C3—C4	1.7 (2)	C5—C4—C11—C16	−55.3 (2)
C1—N2—C3—C4	179.30 (14)	C3—C4—C11—C16	122.98 (19)
N3—C3—C4—C5	177.88 (16)	C16—C11—C12—C13	0.9 (3)
N2—C3—C4—C5	−1.0 (2)	C4—C11—C12—C13	−179.97 (16)
N3—C3—C4—C11	−0.5 (3)	C11—C12—C13—C14	−0.1 (3)
N2—C3—C4—C11	−179.36 (13)	C12—C13—C14—C15	−0.9 (3)
C3—C4—C5—C6	−0.5 (2)	C12—C13—C14—N1	178.82 (16)
C11—C4—C5—C6	177.72 (15)	O1—N1—C14—C15	−177.96 (19)
C3—C4—C5—C8	175.81 (14)	O2—N1—C14—C15	2.7 (3)
C11—C4—C5—C8	−5.9 (2)	O1—N1—C14—C13	2.4 (3)
C4—C5—C6—C7	1.4 (3)	O2—N1—C14—C13	−176.97 (18)
C8—C5—C6—C7	−175.01 (16)	C13—C14—C15—C16	1.0 (3)
C5—C6—C7—N2	−0.7 (3)	N1—C14—C15—C16	−178.65 (17)
C1—N2—C7—C6	−177.78 (17)	C14—C15—C16—C11	−0.2 (3)
C3—N2—C7—C6	−0.9 (2)	C12—C11—C16—C15	−0.7 (3)
C9—O4—C8—O3	0.0 (3)	C4—C11—C16—C15	−179.87 (16)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C9—H9B···O3ⁱ	0.97	2.59	3.295 (3)	130

Symmetry code: (i) −x, −y, −z.

Experimental details

Crystal data
Chemical formula	C₁₆H₁₃N₃O₄
M_r	311.29
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	273
a, b, c (Å)	8.189 (4), 15.821 (8), 11.884 (6)
β (°)	105.380 (8)
V (Å³)	1484.7 (13)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.10
Crystal size (mm)	0.26 × 0.19 × 0.13

Data collection
Diffractometer	Bruker SMART CCD area-detector
Absorption correction	Multi-scan (SADABS; Sheldrick, 1996)
T_min, T_max	0.974, 0.987
No. of measured, independent and observed [I > 2σ(I)] reflections	7569, 2618, 1965
R_int	0.023
(sin θ/λ)_max (Å⁻¹)	0.596

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.042, 0.122, 1.38
No. of reflections	2618
No. of parameters	209
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.18, −0.16

Computer programs: SMART (Bruker, 1998), SAINT (Bruker, 1999), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C9—H9B···O3ⁱ	0.97	2.59	3.295 (3)	130.2

Symmetry code: (i) −x, −y, −z.

Acknowledgements

This work was supported by the Natural Science Fund of Shandong Province (Y2007C135).

References

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Sheldrick, G. M. (1996). SADABS. University of Göttingen, Germany. Google Scholar
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